Phonograph record and method of making



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PHONOGRAPH RECORD AND METHOD OF MAKINC;

Filed Feb. 28, 1941 Patented Apr. I l, 1944 UNITED STATES PATENT OFFICE PHONOGRAPH RECORD AND METHOD or MAKING Walter H. Miller, South Orange, N. J., assignor to Thomas A. Edison, Incorporated, West Orange, N. J., a corporation of New Jersey Application February 28, 1941, Serial No. 381,026

however an object of my invention to overcome 9 Claims.

My invention has especial utility and is herein illustrated and described in connection with hollow cylindrical records of the type commonly used in connection with business phonographs or dictating machines, but it will be understood that no unnecessary limitation of my invention to this type of record is intended.

Phonograph records of the type here mentioned are usually made of a composition permitting the records to be reconditioned for reuse by the process of shaving off the used surface layers of the records. This mode of reconditioning however weakens the structure of the record and renders the record especially liable of in a simple and effective manner this difilculty which is encountered in the use of napp d record-reenforcing materials.

It is another object to prevent the loose particles of napped reenforcing materials from getting into the record proper during record molding by novel and improved means and method; and further it is an object to achieve this result by means of a filter material in a manner wherein the filter material contributes to the strength of the record construction.

being broken from such accidental contingencies It is an object of my invention to provide a record of improved construction which is sufliciently strong to withstand the contingencies of ordinary use, even should the same be in a shaveddown condition.

It is another object of my invention to provide a record with an improved reenforcing member of a nature permitting a firm adherence between this reenforcing member and the record proper, the term record proper being herein employed to mean that portion of the whole record which is actively used for recordation and reproduction purposes.

A particularly desirable material or fabric for reenforcing phonograph records is one having a napped surface as the nap of such materials pro vides a means for obtaining a tenacious grip of the fabric to the record proper. The nap of such materials, however, has some loose particles or fibers, such as fuzz or lint, which tend to escape into the record proper during the molding of the record. These loose particles destroy the fine, even composition of the record and cause the same to have a high level of surface noise. It is Another object is to provide a record construction which has embedded therein a napped reenforcing material and wherein the record proper is free from loose particles, fibers, dirt, etc., such as may be contained in the nap of such a material.

A further object is to manufacture a reenforced record in a manner to effect novel and improved results.

Other and allied objects of my invention will appear from the following description and the appended claims.

In the description of my invention reference is had to the accompanying drawing, of which:

Figure 1 is a longitudinal sectional view of a phonograph record embodying my invention;

Figure 2 is a fractional transverse sectional view of such a record to enlarged scale, this view fractionally showing also in section the core of the mold by which the record is formed;

Figure 3 is a view in longitudinal section and to enlarged scale of a portion of the record here shown; and

Figure 4 is a view illustrating a preferred type of material for reenforcing phonograph records.

In the accompanying drawing there appears a cylindrical phonograph record I which emodies my invention. This record has a central bore 2 extending longitudinally therethrough by way of which the record is mounted on a support or mandrel of a phonograph (not shown). The bore 2 of the record is tapered from one end to the other in order that it may fit a corresponding taper provided on the mandrel, such tapering serving to locate the record on the mandrel and to permit it to be held frictionally thereon. To provide ample bearin engagement between the mandrel and record, the bore of the record is suitably provided with helical ribs or projections 3 and intervening grooves 4. These grooves are of even depth except at the end portion of the record where the bore is enlarged in diameter. Here, starting as at 5 in Figure 1, the bottoms of the grooves are parallel to the longitudinal axis of the record, the same merging with the surface of the bore of the record at points 6 near the record end. In so letting the grooves run out before they reach the end of the record, the record construction is strengthened and other advantages in constructing the record are realized, as are fully explained in my Patent No.'1,976,'795, entitled Sound record tablet.

The ribs or projections 3 are produced in the molding oi the record by means of a fluted mold core I fractionally shown in Figure 2. The molding operation, which is explained in my abovementioned patent, is carried out briefly as follows: A cylindrical mold is provided with the central core 1 and this core is wrapped with a reenforcing liner of a character hereinafter explained. Into the mold there is poured a hot or molten wax-like record material. When this molten record material has sufliciently cooled or congealed, the outer shell of the mold is stripped from the record and the record is removed from the core "I, the record being turned in correspondence with the fluting on the core during such removal. The record is then cut to proper length, the bore of the record is suitably reamed and the outer surface of the record is shaved. It is found that the strengthening capability of a reenforcing material or liner for a phonograph record depends not only on the strength of the liner itself but also in great measure upon the amount of "grip or adherence which the liner has with the record material. To obtain an effective adherence of the liner to the record material it is found important that the liner be provided with a nap constituted of fibers which are firmly secured to the base of the liner and which project largely individually therefrom to form a thick mesh or network. The interstices between these fibers are however to be sufliciently large to permit the molten record material to permeate or percolate therethrough about the individual fibers of the nap so as to cause these fibers to become firmly interlocked with the record material.

A reenforcing material which very suitably fulfills the desired characteristics just mentioned is flannel made of either wool or cotton, the latter being however in many cases the more desirable because of its cheaper cost. In the present instance, I employ a reenforcing fabric 8 made of flannel and having a nap 8 on one side (but which may be on both sides if desired), as shown in-Figure 4. This flannel material is applied to the mold core I with its nap side 8 to the outside, and the wax-like record material, while the same is heated to a suitable state of fluidity, is poured into the mold. In the mold the molten record material percolates through the flannel 8 and passes into grooves I of the mold core to form the helical ribs 3 in the bore of the record. This percolation of the record material through the flannel causes the individual fibers thereofparticularly those constituting the nap of the flannelto become thoroughly embedded in and interlocked with the record material. The great number of these fibers and the considerable distance of their penetration into the record material 'causes a firm adherence between the flannel and the record proper. This firm tenacious adherence has the beneficial eifect of preventing the record from breaking away into separate disunited parts should the record receive a shattering blow.

Cross Reference When a napped fabric is molded into a body of record material, it is found as aforementioned that as the molten record material is poured into the mold-and because of the agitated state of the record material following such pouringsome of the loose particles, fibers or lint of the nap of the fabric are carried out into the record proper. I have found however that this difficulty may be overcome in a simple way by wrapping the flannel 8 with a filter paper 9, which as a typical case may be the paper produced by the Schrieber Press Company and known by them as No. 615. This filter paper is pervious to the molten record material, being of a fine texture having many small interstices through which the molten record material may pass. It is however impervious to the loose particles contained in the nap of the reenforcing fabric as the interstices of the paper are too small to pass these particles. Thus, the filter paper prevents the loose particles of the flannel 8 from becoming distributed throughout the body of the record during the molding operation. In addition, this paper becomes thoroughly embedded in the record, by the many continuous veins of the record material which run through its interstices, and as a result the strength of the paper itself is added to that of the record construction.

While I herein show and describe the filter paper 9 as being separate from the flannel 8, it will be understood that these two materials may well be integrally formed or adhered to one another prior to their use in the record construction. Further it will be understood that various changes and modifications may be made in the invention herein described without departing from the scope thereof, which I endeavour to express according to the following claims.

I claim:

1. A molded phonograph record comprising a body portion of a wax-like material; a napped reenforcing material embedded in said body portion; and a sheet of filtering material embedded in said body portion adjacent the napped surface of said reenforcing material, said filtering material being pervious to molten record material and impervious to loose particles or fibers in the nap of said reenforcing material.

2. A molded phonograph record comprising a body portion, a fabric having a napped surface the fibers of which are embedded in and interlocked with said body portion, and a sheet of porous material embedded in said body portion adjacent the napped surface of said fabric, said porous material being pervious to the molten record material and substantially impervious to loose particles of the nap of said fabric.

3. A molded hollow cylindrical phonograph record having the bore thereof lined with a reenforcing fabric and embedded in the record material, said fabric having a napped surface permeable to the record material when the same is in a molten state; and a sheet of filter paper embedded in the record material about said reenforcing fabric, said filter paper being impervious to loose particles of the nap of said fabric whereby to prevent these particles from becoming distributed through out the record proper during the record molding operation.

4. A hollow cylindrical phonograph record having a reenforcing liner comprised of flannel and of filter paper wrapped about said flannel, said liner being embedded in the material of the record.

5. A reenforcing liner adapted for use in a record which is molded of a wax-like material,

Search Room said liner comprising a napped material and a filter sheet applied to the napped side of said material, said filter sheet being pervious to the record material when in a. molten state and impervious to loose particles of the nap of said liner.

6. A reenforcement adapted for use in a record which is molded of a wax-like material, said reenforcement comprising a fabric of the flannel variety and a filter paper applied to the napped surface of said fabric, said filter paper being pervious to the record material when the same is in a molten stateand at least substantially impervious to the loose particles of the nap of said fabric.

7. In the operation of molding a phonograph record medium about a napped reenforcing sheet while maintaining the record proper free of loose nap from the sheet: the method comprising placing said sheet in a mold; pouring a molten record medium into the mold and into contact with said sheet, said molten record medium being in such state of fluidity that it penetrates the nap of said sheet and is initially in an agitated condition when poured in the mold; and filtering out loose nap from such of the molten record medium adjacent said sheet as flows from the sheet toward the record proper.

8. The method of molding a wax-like record medium about a napped reenforcing material while maintaining the record proper free of loose nap from said reeniorcing material, which comprises flowing a molten wax-like record medium into contact with said napped material, said molten record medium being in such state of fluidity that it penetrates the nap of said reenforcing material and is initially agitated upon being flowed into contact with the reenforcing material and filtering out loose nap from such of the molten record medium adjacent said reenforcing material as flows away from the material whereby to prevent loose nap from being carried, by flow of the molten record medium, from the napped material to the record proper.

9. A phonograph record having a reenforcement therein comprising a sheet of napped material and a filter sheet applied to the napped surface of said material, said reenforcement being embedded within the body of the record.

WALTER H. MILLER. 

